Device and method for irradiating the eye

ABSTRACT

A device and a method for irradiating the cornea of an eye, wherein the device comprises at least the following elements:
         a ring body, which has a bearing surface embodied concentrically about the longitudinal axis of the device for the purpose of fastening the device on the eye,   an irradiation channel for irradiating the cornea, which is located inside the ring body,   a light source, which, in the operationally-ready state of the device, is attached inside the ring body for emitting light in the irradiation channel,   wherein the bearing surface for fastening the device is arranged outside the irradiation channel, which has the result that the irradiated area itself is not additionally loaded by bearing surfaces of the device.

AREA OF THE INVENTION

The invention relates to a device and a method for irradiatingthe—preferably human—eye, in particular the cornea. The device accordingto the invention and the method according to the invention are directedto inducing changes in the structure of the corneal stroma, whichcounteract pathological changes. Thus, for example, keratoconus is adisease of the cornea, which results in increasing weakening of themechanical stability of the tissue due to progressive alteration of thestructure of the corneal stroma. This in turn causes a change of thecorneal geometry, which can result in significant loss of visual acuityup to cornea-based blindness. This applies similarly for keratoglobus,pellucid marginal degeneration (PMD), post-LASIK corneal ectasia,progressive myopia, and other eye diseases.

PRIOR ART

The corneal cross-linking of the collagen fibrils of the cornea by theintroduction of riboflavin into the corneal stroma combined with UV-Airradiation is considered to be prior art. The stability of the corneais thus to be increased and progression of the illness is to beprevented. The geometry of the cornea can also be altered by thecross-linking and a refractive correction can thus be performed on theeye.

Thus, WO 2012/047307 A1 describes a device for irradiating the corneafor the cross-linking of the collagen fibrils of the tissue, afterriboflavin has been introduced as an agent (photosensitizer) into thecornea. The disadvantage of such a system is that the system can performincorrect irradiation of the eye in the event of eye movements.

EP 1561440 A1 and WO 2012/127330 A1 each describe a device for formingand solidifying the cornea by placing a molded body on the cornea,through which the irradiation of the cornea and also the fixation of themolded body or the irradiation unit on the cornea is performed. Thebackground of this invention is the fact that the refractive power(diopter) of the eye is very strongly dependent on the radius ofcurvature of the front face (surface) of the cornea. By way of a newshaping of the corneal surface using a suitable molded body, it is to bepossible, according to the hypothesis of the two documents, to alter therefractive power of the eye by this device in a defined manner. It willnot be discussed here whether this hypothesis is correct. In any case,an essential disadvantage of these two systems is that the suctioningonto the cornea is performed just where the irradiation is alsoperformed, namely flatly on the corneal surface by said molded body.Suctioning on the corneal surface, as described in the two documents ofthe prior art, can easily result in injury of the corneal surface in thesense of corneal erosion, which can cause substantial pain lasting daysfor the patients. The classical method for irradiating the cornea, asdescribed, for example, in WO 2012/047307 A1 is itself linked to cornealerosion and substantial pain, however, there are also newer approachesfor treating keratoconus, where corneal erosion is no longer necessaryand where the treatment can therefore take place without pain (A. Daxeret al. Corneal Crosslinking and Visual Rehabilitation in Keratoconus inOne Session Without Epithelial Debridement: New Technique. CORNEA 2010;29:1176-1179). Especially for those applications in which the epitheliumcan fundamentally be maintained during the treatment, these two devicesfrom EP 1561440 A1 and WO 2012/127330 A1 have a substantial disadvantagebecause of the suctioning onto the corneal surface to be irradiated.

DESCRIPTION OF THE INVENTION

It is therefore an object of the present invention to provide a deviceand a method for irradiating the cornea of the eye, which enablecross-linking of the collagen fibrils while overcoming the disadvantagesof the prior art. Various embodiments of the device and variousassociated methods for treatment are presented. Each embodiment and theassociated method are also to be understood as a starting point forfurther embodiments, in that one or more parts or elements of thepresented embodiments can in turn be combined with one or more parts andelements of other embodiments, so that new embodiments result.

The object is achieved by a device according to claim 1, which comprisesat least the following elements:

-   -   a ring body, which has a bearing surface embodied concentrically        about a longitudinal axis of the device for the purpose of        fastening the device on the eye,    -   an irradiation channel for irradiating the cornea, which is        located within the ring body,    -   a light source, which, in the operationally-ready state of the        device for emitting light into the irradiation channel, is        attached inside the ring body,    -   wherein the bearing surface for fastening the device is arranged        outside the irradiation channel.

Because the bearing surface is provided outside the irradiation channel(specifically outside viewed in the normal direction to the longitudinalaxis of the device or the ring body), the device is only applied to theeye outside the irradiated area in the operating state, the irradiatedarea itself is not additionally loaded by bearing surfaces of thedevice. The device according to the invention thus does not have anyfittings for fastening on the eye inside the irradiation channel, which,in the operationally-ready state of the device, when it is fastened onthe eye, touch the eye. In particular, the irradiation channel can beopen on the side facing toward the eye—in the operating state of thedevice—(=on the side facing away from the light source).

The bearing surface or a diameter of the bearing surface or a diameterof the ring body or a diameter of the suction ring is dimensioned inthis case so that the fastening on the eye preferably takes placeoutside the cornea, or outside the limbus or in the region of theconjunctiva.

The form of the irradiation channel can fundamentally be arbitrary,however, it is embodied at least sectionally along the longitudinalaxis, preferably as an interior (cavity) of a hollow cylinder, and isdelimited by the inner wall of the ring body. The diameter of the exitopening, measured perpendicularly to the longitudinal axis, cannotexceed in this case the internal diameter (smallest diameter) of thesuctioning surface, which is preferably arranged concentrically aboutthe longitudinal axis. In a preferred embodiment variant, the smallestdistance of the delimitation of the exit opening (exit surface) from thelongitudinal axis is not to exceed the smallest distance of the innerbearing edge or the smallest distance of the suctioning surface from thelongitudinal axis. The diameter of the irradiation channel, measuredperpendicularly to the longitudinal axis, is preferably to be at leastsectionally between 0.5 mm and 20 mm and, in a particularly preferredembodiment, is to be between 8 mm and 18 mm, for example, approximately15 mm. The diameter of the exit surface (exit surface, irradiationsurface) from the irradiation channel, measured at the height of the endface of the ring body or the inner bearing edge along the longitudinalaxis, is not to exceed 12 mm if possible and the diameter of the profileof the inner bearing edge or the internal diameter of the suctioningsurface is not to exceed greater than 10 mm if possible, so that thedevice part for fastening on the eye lies outside the irradiated area inany case or delimits it to the outside, measured perpendicularly to thelongitudinal axis. In a preferred embodiment, fittings in theirradiation channel can touch the eye or the cornea, but withoutparticipating in the fastening of the device on the eye (for example,suctioning).

A light source in the meaning of the present invention is to beconsidered any radiation source which can emit electromagnetic radiationin the range of ultraviolet radiation to infrared radiation, but inparticular ultraviolet radiation. In the operationally-ready state, thelight source will generally not protrude beyond the ring body in thelongitudinal direction.

The irradiation channel, which is located inside the ring body, could beformed in a particularly simple manner by the inner wall of the ringbody.

The device according to the invention is essentially embodied as a ringbody, which is arranged essentially (more or less) concentrically aboutthe longitudinal axis. In a particularly simple case, the ring body isimplemented as a hollow cylinder without cover faces, i.e., as acylindrical jacket. The longitudinal axis of the device then correspondsto the cylinder axis. A ring body in the meaning of the presentinvention is any body which has a closed jacket, however, wherein thejacket encloses a longitudinal axis. At least one cavity is inside thejacket, which is open in the longitudinal direction on one side, inparticular on both sides.

The ring body can have a concentric suction ring, which is arranged atone end of the hollow cylinder, for example, and an attachment, which isconnected (in particular mechanically rigidly) to the suction ring, anda receptacle for the functional components, for example, light source,power source or power supply, electronics (control electronics). Theattachment can be embodied in one piece with the ring body, inparticular by way of the other end region of the ring body, facing awayfrom the suction ring. The suction ring can be arranged on the end faceof the ring body which forms the bearing surface.

One embodiment of the invention provides that the light source has afixed, in particular nondetachable mechanical connection to a controlelectronics system for controlling the light source and the controlelectronics system, in the operationally-ready state of the device, arealso attached inside the interior of the device defined by the ringbody. The advantage of this embodiment is that a compact embodiment ofthe device and also a desired profile of the irradiation can be achievedsimultaneously.

In a further embodiment, the functional components light source, powersource or power supply for operating the radiation source, andelectronics system (control electronics system) have a fixed—inparticular nondetachable—mechanical connection among one another, whichalso contributes to the compact embodiment of the device, in particularif the power source is also arranged inside the ring body. The lightsource, power source, and control electronics system could be fixedlyinstalled in the receptacle, for example, and permanently connected tothe attachment or the ring body. The receptacle represents in this casea closed—at least laterally (perpendicularly to the longitudinalaxis)—interior of the device. The functional components are then notreplaceable. That is to say, a receptacle in the actual meaning is notprovided, since the functional components have a fixed, nonvariablespatial relationship to the ring body.

The entire device is preferably embodied as sterile as a medicalsingle-use product. The entire device, including the installedfunctional components, is therefore embodied so that it is sterilizableeither by means of ethylene oxide or gamma radiation. The ring bodyhaving suction ring and all of the outer parts of the device cantherefore be embodied as an injection molded part made of biocompatiblematerial, for example, PMMA or another suitable plastic. The device canfundamentally be embodied from any arbitrary suitable material.

The suction ring has a connector, using which the suction surface can beconnected to a suction pump, so that the ring body is fastened by thegenerated partial vacuum on the eye.

To achieve the most compact possible embodiment of the device, which isonly partially a disposable product, it can be provided that lightsource, control electronics system, and power source are enclosed by ashared housing. The housing can then be inserted into the ring body andalso removed again, so that ring body and housing can be disconnectedbecause of the detachable connection and one of the two parts can bereused.

Accordingly, one variant of the invention is that the ring body has areceptacle for a housing, in which at least the light source, butpreferably further functional components are attached—in particular(mechanically) detachably.

The receptacle can be an integral component of the ring body and can beembodied in one piece therewith, however, it could also be manufacturedas a separate part and then permanently or detachably connected to thering body.

To ensure a defined distance between light source and eye in the case ofthe embodiment with housing in the operationally-ready state of thedevice, it can be provided that the receptacle has a stop limit, so thata housing can be introduced only up to a depth, which is directly orindirectly defined by the stop limit, into the ring body. In order thatthe housing cannot fall out of the ring body—away from the stoplimit—additional holding devices, such as catches or clamp devices, canbe provided.

To prevent a transfer of bacteria from a possibly nonsterile housing tothe ring body and thereafter to the eye, it can be provided that thedevice has a housing envelope, which has a stop-limited receptacle forthe housing, wherein the housing envelope can itself be introduced intothe receptacle for a housing in the ring body, preferably in astop-limited manner. In this case, in the operationally-ready state, thehousing envelope is to enclose the housing on the base and laterallycompletely and in a leak-tight manner and should best protrude on itsupper side.

One embodiment of the invention provides that at least the light sourceis enclosed by a housing, which has a base, which faces toward theirradiation channel in the operationally-ready state and is at leastpartially transparent to the irradiation light, which is generated bythe light source. The light source is thus completely shielded frombacteria, and only the housing, but not the light source, has to besterilized if necessary.

In the case of a housing envelope, it can accordingly be provided thatthe housing envelope has a base, which is at least partially transparentto the irradiation light, which is generated by the light source.

Different settings for the light source can be performed using a controlelectronics system for the light source. In particular, a controlelectronics system can be provided for the light source, using which theirradiation power is settable so that it decreases during theirradiation of the cornea.

The device according to the invention can have a cooling device (forexample, fan, cooling body, cooling liquid, etc.) for dissipating thewaste heat generated by the light source. The remaining components ofthe device are thus subjected to less heat and can be produced frommaterials having lower temperature resistance.

The method according to the invention for irradiating the cornea of aneye using a device according to the invention provides that the deviceis fastened on the eye and the irradiation power is varied during theirradiation of the cornea. To reduce the heating of the device, whichrises with increasing irradiation duration, it can be provided that theirradiation power decreases during the irradiation of the cornea.

BRIEF DESCRIPTION OF THE FIGURES

For further explanation of the invention, reference is made to thefigures in the following part of the description, from which furtheradvantageous embodiments, details, and refinements of the invention canbe inferred. In the figures:

FIG. 1 shows a cross section through an eye with schematic light source,

FIG. 2 shows a longitudinal section through a device according to theinvention fastened on the eye,

FIG. 3 shows the device from FIG. 2 with power source,

FIG. 4 shows an alternative embodiment of the device from FIG. 2 withhousing and housing envelope,

FIG. 5 shows a cooling body for a device according to the invention,

FIG. 6 shows a graph of the power introduced into the eye using thedevice according to the invention as a function of time,

FIG. 7 shows a further graph of the power introduced into the eye usingthe device according to the invention as a function of time.

WAYS OF EMBODYING THE INVENTION

The fundamental structure of the eye and the principle of theirradiation according to the invention are schematically illustrated inFIG. 1. The eye 1 is essentially a hollow sphere, which is delimited atthe front by the cornea 2. The terms anterior and posterior areunambiguously defined in the anatomy of humans. The optical oranatomical axis of the eye, about which the eye 1 is functionally oranatomically arranged coarsely rotationally-symmetrically, is consideredto be the axis of symmetry 3 of the eye. The anatomical axis and theoptical axis are not necessarily coincident. Reference is made to therelevant technical literature with respect to the details on therelationship between optical and anatomical axes. The anterior 4 and theposterior 5 chambers of the eye are separated by the iris 6. The centralopening of the iris forms the pupil 7, through which the light can reachthe posterior chamber 5 of the eye and therefore the retina 8. Adjoiningthe cornea, the sclera 9 forms the outer wall of the eye 1. The sclera 9is externally covered by the conjunctiva at least in the front part ofthe eye. The transition between cornea 2 and sclera 9 is referred to asthe limbus 10. The cornea 2 has a front face (surface), which representsthe external surface of the eye 1 to the front (the outside) and a rearface, which delimits the anterior chamber (anterior chamber of the eye)4 to the front. The axis of symmetry of the eye 1 is to correspond asmuch as possible with the axis of symmetry or longitudinal axis 3 of thedevice. That is to say, the device is to be attached or aligned on theeye 1 as much as possible so that the longitudinal axis 3 of the deviceis aligned on the optical axis or anatomical axis of the eye 1 or anaxis derived from these two axes of the eye. An axis of the eye derivedfrom the optical or anatomical axis is considered, for example, an axiswhich extends through a point on the cornea surface, which extends onthe linear or curved connection section between the passage point of theoptical axis through the cornea (for example, first Purkinje reflex) andthat of the anatomical axis (for example, pupil center point). In thecase of the irradiation according to the invention, light from a lightsource 23 is preferably introduced in parallel to the axis of symmetry 3of the eye 1 into the cornea 2. In a special embodiment, by way ofcollimators, which are introduced into the device (ring body orhousing), an alignment of at least a part of the irradiation light canbe achieved (irradiation direction), which does not necessarily have tobe parallel to the longitudinal axis 3 and can enclose an angledifferent from zero (preferably between 0° and 90°) with the directionof the longitudinal axis.

A preferred embodiment of the device according to the invention isillustrated in FIG. 2. It has a ring body 20, which is implemented hereessentially as a hollow cylindrical jacket. The ring body 20 has at oneend a suction ring 21 for suctioning the device onto the eye 1 duringthe treatment. The suction ring 21 is implemented as a ring-shapeddepression in the end face 25 of the ring body 20, an inner bearingsurface 28 and an outer bearing surface 30 remain of the end face 25inside and outside the suction ring 21. The area between inner and outerbearing surfaces 28, 30, which results by imaginary extension of innerand outer bearing surfaces 28, 30, forms the so-called suction surface29. The end face 25 of the ring body 20, using which the ring body 20bears on the eye 1 in the operating state, is delimited on the insideand outside by bearing edges 24, on the inside by an inner bearing edge27 and on the outside by an outer bearing edge 31.

In this special embodiment, the ring body 20 has a receptacle 22 for alight source 23 for irradiating the cornea 2 or sclera 9. In this case,the suction ring 21 or the ring body 20 is embodied substantiallyconcentrically about a longitudinal axis 3 of the device. Concentricmeans that the suction ring 21 or an equivalent structure, such as thebearing edge 24 or end face 25 (or the inner bearing edge 27, the outerbearing edge 31, the inner and outer bearing surfaces 28, 30), isarranged in a preferably closed, not necessarilyrotationally-symmetrical geometry about the longitudinal axis 3 or acenter point of the structure. Fundamentally, the suction ring 21 or thebearing edge 24 or end face 25 can have any arbitrary (closed) profileshape around a center, preferably the longitudinal axis 3. In this case,in a special embodiment, the longitudinal axis 3 does not have to extendlinearly, but rather can also be curved or angled, or the like, alongits profile. In a special embodiment, the bearing edge 24 is not closedalong the circumference around the center or the longitudinal axis 3. Inthis case, it can be a segmented profile.

The suction ring 21 is separated on the inside, in the direction towardthe longitudinal axis 3, by a bearing edge 27 or inner bearing surface28, which is preferably formed concentrically to the longitudinal axis3, and which is in contact with the eye 1 in the operationally-readystate or which touches the eye 1 or the conjunctiva or the peripheralcornea or the limbus 10, from an irradiation volume or an irradiationchannel 26 or an irradiation opening or an irradiation region. The exitof the light from the device onto the cornea 2 therefore does not occurthrough the ring body 20 or the suction ring 21, but rather in thecentral area (recess of the device) along and about the longitudinalaxis 3 of the device, which is adjoined on the outside, i.e., away fromthe longitudinal axis 3, indirectly or directly by the suction ring 21,which is not penetrated by the irradiation light. In other words, thesuction ring 21 or the inner bearing edge 27 or the inner bearingsurface 28 or the receptacle of the device encloses a central region ofthe device, which is arranged about the longitudinal axis 3, or delimitsit to the outside, wherein the irradiation of the cornea 2 is performedin or through at least one longitudinal section of this central region,namely the irradiation channel 26. The irradiation opening (exit opening19 for the light exit, see FIG. 3) or the irradiation area of theirradiation channel 26, on the one hand, and the suction ring 21 or thesuction surface 29, on the other hand are not congruent and in a specialembodiment are also not overlapping. More precisely, the irradiationarea on the cornea 2, or the projection thereof on the cornea 2 in thedirection of the longitudinal axis 3, and the suction surface 29 of thedevice on the eye 1 are not congruent or not overlapping.

In the present exemplary embodiment, the irradiation channel 26 isimplemented cylindrically and concentrically about the longitudinal axis3, the suction ring 21 is in the form of a circular ring, as are thebearing surfaces 28, 30, the bearing edges 24, 27, 31 are circular. In aspecial embodiment, the cornea 2 can protrude into the irradiationchannel 26 in the operationally-ready state and the irradiation of thetarget tissue can be performed in the irradiation channel 26 or insidethe ring body 20. In the proximal part of the ring body (for example, onthe end face 25 of the ring body), therefore a molded body havingsuction function, through which the radiation light is radiated, istherefore at least not to be attached in any case. An actual exitopening thus does not exist during the treatment, but rather only in thetechnical sense, when the device is not fastened on the eye.

The inner bearing edge 27 or inner bearing surface 28 has a radius of atleast 3 mm, preferably at least 4 mm and ideally between 5 mm and 6 mm,and in a specific embodiment 6 mm or more, about the longitudinal axis3. The suction surface 29 of the suction ring is determined by the area(ring surface) between outer bearing surface 30 and inner bearingsurface 28, wherein the radius of the outer bearing edge 31 (or bearingsurface) is to be at least one-half of a millimeter, preferably greaterthan 1 mm and ideally greater than 2 mm or even 3 mm, larger than theradius of the inner bearing edge 27 measured from the longitudinal axis3 of the device. Thus, for example, the inner bearing edge 27 (bearingsurface) can have a diameter of 12.0 mm or 12.5 mm and the outer bearingedge 31 (bearing surface) can have a diameter of 18.0 mm or 18.5 mm.

In a special embodiment, there is only one of the two bearing edges 24(bearing surfaces 28, 30), so that no special suction surface 29 isdefined. In this case, the suction ring 21 is not embodied as a suctionring in the actual meaning. Independently thereof, the term suction ringalso applies for this embodiment for the entire disclosure. In thiscase, the fastening on the eye is performed only by exerting a manualpressure on the device in the direction of the longitudinal axis towardthe bearing edge.

In a further embodiment, shown in FIG. 2, the inner bearing edge 27(inner bearing surface 28) is offset in relation to the outer bearingedge 31 (outer bearing surface 30) in the direction of the longitudinalaxis 3, to be adapted better to the curvature of the eye or the cornea 2or the sclera 9. This offset is, if possible, to be greater than 1 mmand less than 3 mm, for example, 1.5 mm, 2 mm, or 2.5 mm. In a specialembodiment, the offset is at least 0.5 mm. The bearing surfaces 28, 30do not have to be aligned perpendicularly to the longitudinal axis 3,but rather can additionally also enclose an angle with a planeperpendicular to the longitudinal axis 3 for still better adaptation tothe curvature of the eye 1 or the cornea 2.

The receptacle 22 in FIG. 2 for the light source 23 can simply beimplemented in the interior of the ring body 20 as a shoulder (stoplimit, region having larger diameter than region of the ring body 20located underneath (irradiation channel 26)): the inner, free diameterof the ring body is greater at the height of the light source 23 than inthe irradiation channel 26. The light source 23 can then simply beplaced on this receptacle 22, which is embodied as a shoulder, wherebythe position of the light source 23 is fixed. This is also truesimilarly if a housing is present, which can be introduced into thereceptacle of the ring body when the light source is located inside thehousing and also if a housing envelope is present, into which thehousing is inserted, and which is then inserted into the receptacle ofthe ring body. In these cases, the following applies: In the distal partof the housing (above the stop limit), the housing has an externaldiameter which is greater than the (every) proximal external diameter(below the stop limit). In the distal part of the housing envelope(above the stop limit), the (a) internal diameter is greater than theinternal diameter of the proximal part (below the stop limit) of thehousing envelope. This also applies to the external diameter of thehousing envelope. The external diameter of the housing and the housingenvelope is, at least sectionally along the longitudinal axis,preferably between 2 mm and 20 mm and, in a special embodiment, between6 mm and 16 mm, wherein the wall thickness of the housing envelope(difference between external diameter and internal diameter) ispreferably between 0.1 mm and 2 mm. The mentioned diameters are measuredperpendicularly to the longitudinal axis. The following convention isused for characterizing the direction along the longitudinal axis: Inthe anatomy of humans, the terms distal and proximal are used. Distalmeans away from the body and proximal means toward the body. Thus, forexample, the hand is distal from the elbow joint and the shoulder isproximal from the forearm. Since the present device is provided to beapplied to the body of the human (to the eye), the device has a regionwhich comes into contact with the body during the application of thedevice. This region of the device is the end, measured along thelongitudinal axis, where the suction surface, the bearing surfaces, andthe bearing edges are located and which is referred to in thedescription as lower or therefore, in analogy to the anatomy, withoutthus generating a reference to anatomical structures of the body, asproximal. Therefore, those structures of the device which, measuredalong the longitudinal axis, are relatively more remote from below (fromthe proximal region) are referred to as distal. Thus, for example, thereceptacle for the light source is distal from the suction ring.

The functional components of the device (electronics 32, irradiation orlight source 23, battery 33, etc.) are preferably arranged along thedirection of the longitudinal axis 3, wherein they do not necessarilyhave to be attached along the longitudinal axis 3, but rather can alsobe located at a suitable distance from the longitudinal axis 3 insidethe interior (receptacle) of the device, i.e., for example, inside thering body 20 in FIG. 2.

In a further embodiment according to FIG. 3, the ring body 20 isembodied in conjunction with the receptacle 22 such that the functionalcomponents (light source 23, control electronics system 32 for the lightsource, battery 33 as power source and a switch 46; all connected byelectrical connections 44) are housed in a separate housing 34, which isnot permanently connected to the ring body 20 and the attachment for thereceptacle 22. The attachment for the receptacle 22 is implemented inthis case in one piece with the ring body 20 and forms a part of thering body 20. The receptacle 22 is thus embodied as a exchangereceptacle, which enables the replacement of the functional componentsor the housing 34 from the device or from the attachment with thereceptacle 22, which is connected to the ring body 20. In particular,the receptacle 22 is embodied such that the housing 34, which containsthe functional components, can be introduced in a stop-limited mannerinto the receptacle 22 and also removed from the receptacle 22 again.The housing 34 also has a corresponding stop limit 35 which, incooperation with the stop limit 36 of the receptacle 22, prevents aninsertion of the housing 34 into the receptacle 22 beyond a defineddepth. A defined distance 37 of the light source 23 from the cornealsurface (or from the end face 25 of the ring body 20) and therefore adefined irradiation strength at the corneal surface is thus guaranteed.The distance of the light source 23 from the end face 25 of the ringbody 20 or from the inner bearing edge measured in the longitudinal axis3 is generally greater than 1 mm, preferably greater than 3 mm and, in aspecial embodiment, greater than 10 mm, but less than 70 mm, preferablyless than 50 mm, and ideally less than 30 mm.

In the embodiment of the invention according to FIG. 3, the ring body 20having attachment and receptacle 22 can be embodied from aresterilizable biocompatible material, for example, steel or titanium,and the housing 34, which contains the functional components, forexample, can be embodied as a simple injection molded parts made ofplastic, for example, made of PMMA, because the housing 34 is embodied,for example, as sterile (for example, ethylene oxide sterilization) as asingle-use product.

The housing 34 can be embodied with or without base 38. The base 38 isused in this case as a window, which is either completely transmissiveto the irradiation light or is differently transmissive in a spatiallyselective manner viewed over the irradiation area in dependence on thedistance from the longitudinal axis 3 (radial) or the circumferentialposition of about the longitudinal axis (circular), i.e., depending onthe location on the window surface measured perpendicularly to thelongitudinal axis (i.e., at different locations at the passage points ofthe irradiation light through the window) and can therefore act as abeam profile converter (see below) in specific embodiments. The window38 can also be embodied so that during the passage of the light throughthe window, the exit angle of the irradiation light from the window isdifferent from the entry angle into the window, measured in relation tothe longitudinal axis 3 of the device. The irradiation light is thusrefracted during the passage through the window from or toward theperpendicular. The window can also be embodied so that the extent ofthis light refraction (angle change) is dependent on the position, i.e.,the location on the window surface, i.e., on the distance from thelongitudinal axis 3 or even on the position on the window surface, whichextends perpendicularly to the longitudinal axis 3. The mentionedfunctions of the window can also be caused by suitable components whichare attached above (distally) or below (proximally) to the window,measured in the direction of the longitudinal axis, for example, bycomponents in the form of inlay elements (for example, lamina) in thehousing envelope.

In a special embodiment, a further or other window, which can also havethe above-described properties, can be attached at another point insideor outside the housing 34 along the direction of the longitudinal axis3, but in the irradiation direction after the light source 23. Thewindow (the area or substance of the window) extends essentiallyperpendicularly to the longitudinal axis 3, although it can also have adiffering or variable thickness along this extension. The thickness ateach point of the extension (area) of the window is measured in thedirection of the longitudinal axis 3.

Instead of the installed battery 33, an external current or voltagesource can also be used. The battery 33 can also be provided externally,i.e., not in the device which can be placed on the eye, and connectedusing a cable or wire to the control electronics system 32.

In a further embodiment according to FIG. 4, in the operationally-readystate, in addition as an intermediate part between housing 34 for thefunctional components and the receptacle 22 (stop-limited exchangereceptacle) of the attachment or ring body 20, a housing envelope 39 isattached, which itself in turn has an internal stop limit 40 for thestop-limited receptacle of the housing 34 and externally has a stoplimit for the receptacle of the housing envelope 39, which receives thehousing 34, in the receptacle 22 of the ring body 20. The housing 34,which contains the functional components (light source 23, controlelectronics system 32, battery 33, switch 36) thus does not have to beembodied as sterilizable, or does not have to be sterile. The housingenvelope 39, which is to accommodate the housing 34, can therefore beembodied as a very simple and cost-effective injection-molded part madeof biocompatible plastic (for example, PMMA) which is sterilizable usingethylene oxide or gamma radiation, as a single-use product. The externalpart of the device, i.e., the ring body 20 (having suction ring 21,attachment, and receptacle 22) can be manufactured as a reusable part,for example, for steam sterilization, for example, from steel ortitanium or another suitable biocompatible material. In order that thesterility of the device can be ensured during the operation in thisembodiment and a transfer of bacteria from the nonsterile housing 34 tothe operating field is prevented, the height of the housing envelope 39,measured in the direction of the longitudinal axis 3, must be greaterthan that of the housing 34. The height of the housing envelope 39 inthe operating state is preferably at least 1 mm greater than the heightof the housing 34. The height of the housing is measured from the lowerside 38 up to the upper edge 43 of the housing in the direction of thelongitudinal axis 3. The height of the housing envelope is measured fromthe lower side 45 up to the upper edge 42 of the housing envelope in thedirection of the longitudinal axis 3. This height difference 41 betweenhousing 34 and housing envelope 39 is ideally greater than 2 mm,however, for example, 5 mm. In other words: the upper edge 42 (upperside) of the housing envelope 39 protrudes beyond the upper edge 43(upper side) of the housing 34 in the operationally-ready state, i.e.,when both are introduced in a stop-limited manner into the associatedreceptacles 22 of the ring body 20 or into the receptacle of the housingenvelope 39, respectively, by more than 1 mm, preferably more than 2 mm,or ideally more than 5 mm. The upper edge is the point or edge orsurface of the housing 34 or the housing envelope 39 which is the mostdistally remote from the body (eye 1, cornea 2) in theoperationally-ready state. Thus, the point or edge or surface which ismost remote from the suction ring 22, measured along the longitudinalaxis 3. The suction ring 21 is proximal (below, rear). The receptacle 22is distal (above, front).

In the operationally-ready embodiment according to FIG. 3, the ring bodyis preferably embodied as sterile (resterilizable) from metal or ceramicand the housing is embodied as sterile, preferably as a single-useproduct.

In the operationally-ready embodiment according to FIG. 4, the ring bodyis preferably embodied as sterile, the housing envelope as sterile, andthe housing as nonsterile. Possible destruction of functional componentscan thus be avoided during the sterilization.

The device is preferably placed or attached in the operationally-readystate on the eye 1 so that the longitudinal axis 3 of the device isaligned essentially perpendicularly to the sagittal body plane, orapproximately in the direction of the optical or anatomical axis of theeye 1. The longitudinal axis 3 of the device is preferably to correspondapproximately to the extension direction of the optical axis or theanatomical axis of the eye, or is to continue it. The passage of thelongitudinal axis 3 of the device through the passage opening (passagearea) 19, which is enclosed by the suction ring 21, for the irradiationlight (irradiation area, irradiation opening, . . . ) defines a centerpoint (center), about which the suction ring 21 is concentricallyarranged. This center point is, in the operationally-ready state,preferably to correspond approximately to the center point (center) ofthe cornea 2, which results from the passage point of the optical axisor the anatomical axis through the cornea 2. It is thus ensured that nodamage to the limbal stem cells occurs, i.e., the limbus 21 issubstantially excluded from the irradiation.

In various embodiments, the longitudinal axis 3 of the device can bealigned on different axes of the eye, i.e., continuing these axes of theeye. Thus, in one specific embodiment, the longitudinal axis 3 of thedevice can be aligned on the optical axis, or on the anatomical axis, oron an axis which lies between the optical axis and the anatomical axis.

The functional elements, e.g., light source 23, electronics system 32,battery 33, are also connected to one another by wire or cable(electrical connections 44) in this embodiment.

In one specific embodiment, the housing envelope 39 has an opening onthe upper side (upper edge 42) for the insertion of the housing 34 intothe housing envelope 39, preferably up to the stop limit 40. The housingenvelope 39 or at least the window of the housing envelope is preferablyembodied as transparent to the irradiation light.

In one specific embodiment, the properties of the lower side 45 (window)of the housing envelope (45) can entirely or partially correspond tothose described above in FIG. 3 for the lower side (the base/the window38) of the housing 34 and can act or be embodied at least partially as abeam profile converter.

In all embodiments having exchange receptacles, the replaceable elementsof the device, such as housing 34 or housing envelope 39, are preferablyinserted in the direction of the longitudinal axis 3 from above(distally), that is the end of the device (of the ring body 20) oppositeor facing away from the cornea 2 or the suction ring 21.

The parts of the device which have a exchange receptacle (ring body 20having receptacle 22, housing envelope 39) are embodied as open upward(distally), for example, on the upper edge 42.

In one specific embodiment, a switch 46 for turning on the light source23 (for example, UV LED) is embodied as a mechanical switch. In anotherspecial embodiment, this switch 46 is embodied as contactless, forexample, in that the housing 34, which contains the functionalcomponents, also has a magnetic sensor having switch or switch function,which is capable in the event of sufficient magnetic field of turning onthe operating current for the light source or triggering the beginningof the irradiation and, in a further specific embodiment, also the end(the termination) of the radiation. In one specific embodiment, theirradiation time can also be defined or controlled via an internal,preferably electronic timer or clock, in that, for example, afterturning on the irradiation by triggering a magnetic or other switch,after a specific preprogrammed time, the radiation is turned offautomatically, i.e., without external action, by means of an internaltimer (electronic timer inside the device (control electronics system32)).

In one special embodiment, the turning on and/or off of the irradiationoperation by the device is triggered by means of a sterile magnet 47 ormagnetic rod, which is moved sufficiently close to theoperationally-ready device by the operator or an operation assistantduring the operation. In this case, the magnetic switch 46 is preferablylocated inside the housing 34. In this case, the magnet 47 or magneticrod is part of the device.

Operationally ready is understood as the state of the device in whichthe respective parts of the device (depending on the embodiment ringbody 20 (having suction ring 21), receptacle 22, housing 34, housingenvelope 39, etc), are assembled and are in such a state (for example,temperature) that after the device is turned on (irradiation) it can betherapeutically used immediately in just this state.

The energy or radiant power transferred to the cornea 1 is the energy orradiant power which, depending on the embodiment, is preferably measuredat a distance of 1 to 5 mm (for example, 3 mm) from the inner bearingedge 27 or from the end face 25 of the ring body 20 or between lowerside of the housing envelope and 5 mm proximally to the lower side ofthe housing envelope (=between housing envelope and end face of the ringbody), in each case on the longitudinal axis 3 and in each case insidethe irradiation channel 26.

The irradiation channel is delimited proximally by the end face 25,distally by the light source 23, and laterally by the inner wall 48 ofthe ring body 20. In this case, the wall of the ring body 20 can befenestrated, i.e., have openings.

For conventional irradiation by means of UV-A light with cornealcross-linking, a total energy of 5.4 J/cm² is to be transferred to thecornea 2. This total energy results from the multiplication of the powertransferred to the cornea 2, which is normally between 3 mW/cm² and 30mW/cm², by the irradiation time, which is accordingly between 180seconds and 1800 seconds. In one specific embodiment, the timer is set(embodied) so that these conditions are met. In one special embodiment,the internal timer of the device is set (embodied) so that the devicetransfers an energy of less than 5.4 J/cm² to the cornea 2 during theirradiation. In one specific embodiment, the internal timer of thedevice is set (embodied), with preset irradiation power between 3 mW/cm²and 30 mW/cm² so that the energy transfer to the cornea 2 during thetreatment time limited by the timer is less than 5.4 J/cm², inparticular less than 5 J/cm², and very preferably less than 3 J/cm²,preferably less than 2.5 J/cm² and ideally between 1.5 J/cm² or 1.8J/cm² or 2.0 J/cm² and 2.5 J/cm², for example, approximately 1.8 J/cm²,approximately 2.1 J/cm², approximately 2.2 J/cm², or approximately 2.3J/cm². This means that the device or the timer (time switch)automatically turns off the irradiation after a time when the desiredirradiation energy is reached according to the above considerations.

The internal timer (time switch) of the device therefore turns off theirradiation of the cornea 2, for example, according to following Table1, depending on the embodiment, after the following irradiation time:

TABLE 1 Power (mW/ Irradiation Energy Irradiation Energy IrradiationEnergy cm²) time(s) (J/cm²) time(s) (J/cm²) time(s) (J/cm²) 3.00 720.002.16 780.00 2.34 600.00 1.80 6.00 360.00 2.16 390.00 2.34 300.00 1.809.00 240.00 2.16 260.00 2.34 200.00 1.80 12.00 180.00 2.16 195.00 2.34150.00 1.80 15.00 144.00 2.16 156.00 2.34 120.00 1.80 18.00 120.00 2.16130.00 2.34 100.00 1.80 21.00 102.86 2.16 111.43 2.34 85.71 1.80 24.0090.00 2.16 97.50 2.34 75.00 1.80 27.00 80.00 2.16 86.67 2.34 66.67 1.8030.00 72.00 2.16 78.00 2.34 60.00 1.80

The irradiation power in mW/cm² (or in mW upon observation of the totalirradiated area) can be constant in this case during the irradiationtime or can vary or oscillate around a specific value (or around aspecific curve—see below). In a further embodiment, the irradiationpower can follow a defined curve during the irradiation time, forexample, linearly increasing or decreasing, nonlinearly increasing ordecreasing, periodically varying, non-constantly linearly increasing ordecreasing (i.e., during the irradiation time, the irradiation powerincreases or decreases linearly or nonlinearly in different strengths atdifferent phases during this irradiation time), exponentially increasingor decreasing, etc., or an arbitrary combination of these curve forms.

Thus, for example, a non-constantly decreasing irradiation curve couldfollow the following law, for example:

irradiation power(t)=k1*t+k2*t+k3*t+f(t),

wherein k1, k2, k3, within the irradiation time or within a specifictime phase during the irradiation time (wherein duration of the timephase is less than or equal to irradiation time) or in different timephases within the irradiation time, can be different constants or zeroand f(t) can also be linear, multilinear, arbitrary, or zero within theirradiation time or in different time phases can in each case bedifferently linear, multilinear, arbitrary, or zero.

An embodiment variant in which the transferred total energy isapproximately 5.4 J or 5.4 J/cm² and in which the irradiation powerdecreases with time, can appear as follows, for example (Table 2):

TABLE 2 Zeit (s) Leistung (mW/cm2) Energie (mJ/cm2) 15.00 17.80 277.5030.00 16.70 536.25 45.00 16.30 783.75 60.00 15.80 1024.50 75.00 15.401258.50 90.00 14.80 1485.00 105.00 14.30 1703.25 120.00 13.80 1914.00135.00 13.40 2118.00 150.00 13.00 2316.00 165.00 12.60 2508.00 180.0012.30 2694.75 195.00 12.00 2877.00 210.00 11.70 3054.75 225.00 11.403228.00 240.00 11.20 3397.50 255.00 11.00 3564.00 270.00 10.85 3727.88285.00 10.60 3888.75 300.00 10.40 4046.25 315.00 10.20 4200.75 330.0010.10 4353.00 345.00 10.00 4503.75 360.00 9.91 4653.08 375.00 9.904801.65 390.00 9.85 4949.78 405.00 9.80 5097.15 420.00 9.75 5243.78435.00 9.71 5389.73 Zeit = time Leistung = power Energie = energy

This is shown in a graph in FIG. 6. The power in mW/cm² is indicated onthe left vertical axis, the cumulative energy in mJ/cm² is indicated onthe right vertical axis, and the time in seconds is indicated on thehorizontal axis. In this case, the power (time curve 61 of theirradiation power) is shown decreasing, which transfers due to itsspecial time curve a cumulative energy 62 to the cornea 2, which, at theend of the irradiation duration has thus transmitted the cumulativetotal energy of approximately 5.4 J (or 5.4 J/cm²) to the cornea 2. Themean irradiation power 63 results from the cumulative total energydivided by the irradiation duration.

Another embodiment variant, in which the total transferred energy isapproximately 2.1 J or 2.1 J/cm² and in which the irradiation powerdecreases with time, can appear as follows, for example (Table 3):

TABLE 3 Zeit (s) Leistung (mW/cm2) Energie (mJ/cm2) 15.00 17.80 277.5030.00 16.70 536.25 45.00 16.30 783.75 60.00 15.80 1024.50 75.00 15.401258.50 90.00 14.80 1485.00 105.00 14.30 1703.25 120.00 13.80 1914.00135.00 13.40 2118.00

This is shown in a graph in FIG. 7, wherein FIG. 7 reflects therelationships of FIG. 6, but using a cumulative total energy ofapproximately 2.1 J (or 2.1 J/cm²) instead of 5.4 J (or 5.4 J/cm²). Thevariables plotted on the individual axes correspond to those in FIG. 6.

In one preferred embodiment, the irradiation power decreases during theirradiation time or at least at the beginning of the irradiation timewith increasing duration. That is to say, the irradiation power is lessat a later point in time within the irradiation time than at an earlierpoint in time within the irradiation time. In a special variant of thisembodiment, the decrease of the irradiation power decreases during theirradiation time. That is to say, in a later phase of the irradiation,the irradiation power decreases less strongly with time than in anearlier phase.

The transferred irradiation energy (total energy) is calculated from theintegral of the time-dependent irradiation power over the irradiationtime. The irradiation time is calculated from the duration which isrequired to reach the required total energy which is to be transferredto the cornea 2. This value is set (programmed) in a timer of thecontrol electronics system 32 during the manufacturing.

This property, specifically that the power decreases during theirradiation, can be advantageous in that the technical requirements forthe cooling or heat dissipation of the light source 23 in theoperationally-ready state or during the operation are reduced and thecosts of the manufacturing can thus be decreased. More advantageousmaterials can thus also be used in relation to the transparency of thehousing (window) and the device can be constructed as particularlysmall, which is in turn accompanied by advantages in the medicalapplication.

This is preferably a UV, in particular a UV-A light source 23 forirradiating the cornea 2 in this case. In a very special embodiment, thelight source 23 is a light-emitting diode, which emits, for example, inthe UV-A range, for example, light in a wavelength range between 350 nmand 370 nm (380 nm), for example, at 360 nm or at 365 nm or at 370 nm. Avariation or inaccuracy of the functioning range of up to 10% aroundthese values can be tolerated in specific embodiments. However, thislight source 23 can also emit in a completely different wavelength range(visible or nonvisible) if an active agent for cross-linking or otherinfluence of the collagen fibrils or another stabilizing element of thecornea 2 or this element itself are active in this wavelength range.Active in this context means that by way of the irradiation from thelight source 23, with or without the aid of an agent (for example,riboflavin, hyaluronic acid, etc.) to be introduced into the cornea 2 orsclera 9 to mediate the effect, the cornea 2 is structurally orultra-structurally changed such that a stabilization or shape change orrefraction change or other change of the cornea 2 or sclera 9 isachieved. A stabilization can be the inhibition or slowing of theprogress of an illness or refraction anomaly or at least local hardeningor shrinking of the tissue. The irradiation source (light source 23) canalso consist of multiple individual irradiation sources (light sources)which can be arranged in any arbitrary position in relation to oneanother and which, in special applications, can also have differentwavelengths or wavelength ranges in the emission characteristic. Theirradiation sources or light sources can be attached at arbitrarylocations inside the device, also outside the housing 34, preferably,however, all light sources are attached inside the housing 34.

The light source 23 or light sources can emit spatially orchronologically homogeneous or inhomogeneous electromagnetic waves forat least partial absorption in the cornea 2 or sclera 9. In a spatialaspect, the light source 23 can have a uniform intensity profile overthe emission area or over the emission cross section, or a preferreddirectional characteristic, which can have intensity maxima in one ormore different directions, for example. Thus, for example, a directionalcharacteristic can be “club-like” having a specific opening angle (forexample, 80°).

In another embodiment, the wavelength of the light source 23 is between250 nm and 300 nm, in particular between 270 nm or 290 nm, or around orat 280 nm. The wavelength and the irradiation intensity of the cornea 2are preferably selected so that no tissue ablation occurs on the corneadue to the irradiation. In one preferred embodiment, the wavelengthand/or the irradiation intensity is selected so that a tissue ablationon the cornea is precluded.

In one special embodiment, however, the wavelength and the energy of thelight source 23 (irradiation source) can be selected, however, so that atissue ablation can be achieved on the cornea 2. In this exemplaryembodiment, the wavelength is preferably to be between 180 nm and 230nm. The energy is to be between 0.1 and 10 J/cm². The irradiated area onthe cornea 2 is not to exceed a diameter of 12 mm, ideally it is to be10 mm or smaller in diameter (for example, 9.5 mm, 9 mm, 8.5 mm, or 8mm). The irradiated area is ideally approximately 1 cm² in size.

The irradiation or light source 23 (for example, LED) is, in a specificembodiment according to FIG. 5, directly or indirectly thermallyconnected to a solid, metallic, liquid, gaseous, ointment-like or pasty,greasy, creamy, amorphous, crystalline or other cooling body 50 or amass inside the housing 34. The cooling body 50 or the mass is capableof absorbing at least a part of the heat generated by the light source23. In other words: The temperature of this cooling body 50 increases onat least one point or area on its surface or in the body interior. Thiscooling body 50 is preferably at least 2 mm wide (measured in at leastone dimension perpendicular to the longitudinal axis 3) and at least 2mm tall (measured in the direction of the longitudinal axis 3). Ideally,this cooling body 50 is attached directly to the light source 23 bydirect contact on a contact surface 51, wherein the distance between thecooling body 50 and a point on the external surface of the light source23 is ideally zero if possible, but at least less than 2 mm, preferablyless than 0.5 mm. The light source 23 can also be in contact with aliquid and/or a liquid can wash around it inside the housing 34. Theirradiation light then penetrates this liquid. This liquid is capable ofabsorbing heat from the light source 23. The liquid thus heats up duringthe irradiation time.

In one special embodiment, the temperature of the device, in particularof the light source 23 and/or the ring body 20, in anoperationally-ready state is less than 5° C., preferably less than 1°C., and ideally 0° C. if possible. In a further embodiment, thetemperature of the device, in particular of the light source 23 and/orthe ring body 20, displays a time-dependent curve during operation(=light emission from the light source). For example, the device isembodied so that the temperature of the device, measured at the lightsource 21 and/or the ring body 20, during operation (=for example,during the duration between turning on the irradiation operation andturning off the irradiation operation as induced by the internal timer)increases from a starting temperature (for example, 0° C.) in theoperationally-ready state (starting state, before the turning on orbefore the point in time of the turning on of the device) to highertemperature values (for example, greater than 0° C., preferably greaterthan 1° C., and in particular greater than 5° C.).

However, the light source 23 can also emit in another UV range, in thevisible light range, or in the infrared range.

Solid-state lasers (neodymium or titanium lasers—for example, Nd:YAG,Nd:glass, Nd:YLF, Ti:Sa) can also be used as the primary light sources.Corresponding harmonics of a basic wavelength can also be generated.Double-refractive crystals such as BBO, KDP, KTP, or Li-niobate can beused for this purpose.

The current supply for operating the light source 23 can be producedlocally via an “installed” (internal power source) battery 33 or anaccumulator cell or, however, via a current line between light sourceand power source (battery, accumulator cell, power supply unit, ortransformer) (external power source). “Installed” in this context meansthat the power source is permanently connected to the light source 23such that it can be inserted jointly with the light source 23 into theinsert of the suction ring (i.e., into the ring body 20), even if partsthereof protrude out of the ring body 20 or the receptacle 22. Thisconnection can be performed, for example, by a shared housing 34, whichnot only electrically but also mechanically connects light source 23 andpower source 33 such that the power source 33, due to the mechanicalconnection to the light source 23, automatically also has to be moved oris moved during the movement thereof (for example, insertion into thering body 20). In other words, the power source 33 is seated fixedly orpermanently connected by a mechanical device, at least during theintended use, on the light source 23. This can be implemented by ashared housing 34 or in the form of a shared base plate or othermechanical connecting elements between light source and energy source23, 32.

By way of the attachment of the illumination unit (device) on the eye,which is achieved via the ring body 20 fastened on the eye 1, anyuncertainty and incorrect illumination of the eye as a result ofintentional and unintentional eye movements is prevented. WO 2011/138031A1 does describe a tracking system for an illumination beam in the senseof a scanning spot beam to ensure a local irradiation distribution andto preclude errors due to eye movements, however, this system is verytechnically complex and costly. The possibility is accordingly providedby the fixation or possible fixation according to the invention of thedevice on the eye that the light source 23 (irradiation source) isitself also tracked with the eye movements and not only the beam fromthe light source 23 is deflected accordingly.

In a further embodiment of the present invention, a homogenizer can beinstalled to homogenize the active irradiation profile (intensityprofile of the light source 23) in the irradiation channel 26 (betweenlight source 23 and the end face 25 of the ring body 20) at least 1 mmproximally of the irradiation source (light source 23). This homogenizeris to produce a homogeneous intensity profile by “mixing” the primarybeam profile between light generation inside the device and light exitfrom the homogenizer before the incidence on the corneal surface. Such ahomogenizer can be embodied, for example, in the form of a reflectivehollow cylinder, the cavity of which is aligned along the cylinder axis(longitudinal axis 3) or at a specific angle to the irradiationdirection. (Such) a homogenizer can also be arranged concentrically orinclined or offset in parallel or a combination of these arrangements tothe irradiation direction (which can be established, for example, by thelongitudinal axis 3 between light source 23 and end face 25 of the ringbody 20). The reflector surface of the homogenizer in the interior canbe smooth or rough or uneven. It can have protrusions or projections,which reflect or do not reflect. The reflector surface can also have aspiral or circular—symmetrical or asymmetrical—surface design. Ahomogenizer can be implemented particularly simply if the irradiationchannel 26 is formed by the inner wall 48 of the ring body 20 (see FIG.4), because then the inner wall 48 can simply be implemented accordinglyas a reflector surface.

In a further embodiment, the homogenized (homogenizer) ornon-homogenized radiation profile (intensity profile) of the lightsource 23 can be converted into a radiation or intensity profile ofspecific characteristic by a suitable device, which is attached in theoperationally-ready state between the light source 23 and the tissue tobe irradiated (for example, cornea 2) or at a distance of at least 1 mmremote from the light source (proximally) or at least 1 mm remote fromthe end face 25 (distally) inside the irradiation channel 26. Thisdevice (beam profile converter) can be attached before or after thehomogenizer if a homogenizer is present. If a homogenizer is notpresent, the beam profile converter is attached between light source 23at a distance of at least 1 mm from the end face 25 and/or at least 1 mmfrom the radiation source inside the irradiation channel 26 (i.e.,between light source and target tissue). The beam profile converter canbe directly or indirectly mechanically connected to the ring body 20 oralso, as already stated above, arranged in the housing 34, attached onthe window (base 38, lower side) of the housing 34 or can replace thiswindow or can be attached on the window (lower side 45) of the housingenvelope 39 or can replace this window. In one specific embodiment, itcan be permanently connected to the ring body 20 or can be replaceableor exchangeable—i.e., it can be inserted or removed. This can be used,for example, to compensate for the differing energy density of the lightupon incidence on target tissue (cornea 2) is curved or inclined inrelation to the irradiation direction in joules per unit area or Wattsper unit area. Such a device for modification of the beam profile (beamprofile converter) can consist, for example, of an insert or at leastpartial optical obstruction in the illumination beam path between thelight source 23 and the target tissue (for example, at a distance of atleast 1 mm from the end face 25 and/or at least 1 mm remotely from thelight source inside the irradiation channel 26). This device (insert,housing, housing envelope, etc.) for beam modification is characterizedin that it represents a transmission obstruction over at least a part ofthe irradiation area (intensity profile). In a special embodiment, thiscan be achieved by a lamina which is introduced into the beam path andconsists of a material which displays an absorption behavior for thewavelength used. The intensity variation (beam modification) over theirradiation cross section (irradiation area) can be achieved in thiscase by thickness variation of the lamina over the illumination crosssection. In this case, the thickness variation measured in the directionof the longitudinal axis of the lamina over the illuminationcross-section measured perpendicularly to the longitudinal axis is adepiction of the desired intensity variation. The illumination crosssection is considered the cross-sectional area within the irradiationchannel proximally of the illumination source (i.e., betweenillumination source and end face or bearing edge) which extendsperpendicularly to the longitudinal axis and is delimited by the innerwall of the ring body. In the case of a nonhomogeneous beam profile,before the incidence on the lamina, the thickness variation must beweighted in accordance with the non-homogeneity of the primary beambefore the incidence on the lamina to generate the desired finalintensity profile upon incidence on the target tissue. In the case of ahomogeneous primary beam before incidence on the lamina, for example, tocompensate for the effective drop of the light action on the peripheraltissue as a result of the cornea curvature, the lamina must have athickness distribution in which the thickness preferably decreasessymmetrically from the inside (approximately corresponding to theoptical axis) to the outside (light beams incident on the peripheralcornea). The extent of the thickness or the thickness reduction isdependent on the absorption behavior of the lamina (for example, windowin the base 38 or window in the lower side 45), i.e., the coefficient ofabsorption, and the precise or approximate curvature profile of thecornea 2 (depending on the required precision of the correction) towardthe outside. However, the variation of the cornea thickness or anyarbitrary other possible reason for a fundamentally arbitrary variationof the lamina thickness, or a combination of reasons, can be used forvariation of the irradiation intensity.

Such a beam profile converter can also be used, with slight variation ofthe components for the primary light source 23 (tolerance of thecomponents) with respect to beam characteristic of the primary lightsource 23 (photodiode, light-emitting diode, UV light source, LED,laser, laser diode, etc.) as a homogenizer.

To change or limit the beam diameter of the irradiation light, in theoperationally-ready state, an aperture or an aperture system can beattached (for example, in the housing 34 or in the housing envelope 39or on the ring body 20) inside the irradiation channel 26 or at the exitof the irradiation light from the irradiation channel 26. Such anaperture or such an aperture system consists of a material which isnontransparent to the wavelengths of the irradiation light having atleast one or more transparent light passages applied thereon. Theselight passages can have an arbitrary shape, for example, they can beround, circular, elliptical, star-shaped, polygonal, or other. Theapertures can be embodied as inlay lamina to be laid in the housingenvelope 39. The light passages can have dimensions (for example,diameter or greatest extension) of 0.01 mm to 10 mm, measuredperpendicularly to the longitudinal axis 3. The aperture can also beembodied as an “inverse aperture”, in that at least one nontransparentarea is at least partially enclosed by a transparent area.

In the case of all fittings (homogenizer, beam profile converter) in theinterior of the ring body which protrude into the irradiation channel26, it is to be ensured that they do not touch the cornea 2 in theoperationally-ready state of the device. In this regard, thesefittings—viewed from the light source 23 in the direction of thelongitudinal axis 5—should be arranged in front of the end of the ringbody 20, in particular at a distance of at least 1 mm remote from theinner bearing edge 27 (see FIG. 2).

The ring body 20 (or its linear outer wall 49, see FIG. 4) has, in theoperationally-ready state, measured in the direction of the longitudinalaxis 3, a height of at most 150 mm, ideally at most 70 mm and at least10 mm. The light source 23 is at least 1 mm remote from the base 38 inthe housing 34. The light source 23 is, in the operationally readystate, at least 1 mm, at most 150 mm, remote from the inner bearing edge27 of the ring body 20. A typical height of the ring body 20 isapproximately 30 mm and the entire device, including housing 34 andhousing envelope 39, is approximately 60 mm.

The device according to the invention for irradiating the target tissuecan also contain an electronics system (control electronics system 32)for current limiting for the current supply of the primary light source23. This electronics system 32 can achieve this current limiting eitherby pulsation of the light source 23 with fixed or variable pulseduration for the power control of the primary light source or bylimiting the current strength by ohmic or active components. Theelectrical activation of the light source 23 can be performed in aspecial embodiment via a constant current source, wherein the currentthrough the irradiation source is to be at values around 100 mA (50 mAto 200 mA). The pulsation (pulse duration or relative pulse duration inrelation to the period length) of the light or of the activation currentof the light source can be arbitrary. A pulsation of approximately 1:2for the ratio of pulse duration to period duration is advantageous. Thepulsation can preferably be between 1:1 and 1:5. For example, at 1:1.5,1:2, 1:3, 1:4, 1:5 or also greater than 1:5. The pulse duration can bein the range of seconds, ms, ns, ps, or less.

The standby current of the electronics system 32 is to be in themicroampere range if possible, i.e., less than 100 μA, preferably lessthan 10 μA.

The irradiation intensity, power, and energy at the target tissue can beoriented, inter alia, according to the choice of the selected activeagent in the target tissue, according to the desired irradiationduration, according to the desired two-dimensional action distribution(effect) along the surface of the target tissue (for example, corneasurface), according to the depth or depth distribution in the targettissue, according to the wavelength or the wavelength spectrum of thelight source 23 (primary light source or upon incidence on the targettissue, or upon exit from the device), etc.

In one specific embodiment, the emitted power of the device on thetarget tissue, i.e., the power immediately after the light source 23(for example, less than 1 mm remote from the light source) can bebetween 1 and 30 mW/cm², preferably between 3 and 20 mW/cm². In furtherembodiments, the emitted power can be between 3 and 15 mW/cm² or between3 and 9 mW/cm². The power can be set (embodied) variably between thespecified values or fixedly at a specific value in one of the specifiedranges. Thus, in embodiments having fixed power setting, for example, 3,6, 9, 10, 12, 15, 20, 25, or 30 mW. In one specific embodiment, thepower can be greater than 30 mW/cm². In these cases, emitted powers of30, 35, 40, 45, or 50 mW/cm² are thus conceivable.

In one embodiment, the current strength for activation or for operationof the primary light source 23 (for example, UV LED), can be limited toless than 700 mA. In a further embodiment, this current strength can belimited to less than 200 mA. In further embodiments, the device containsa voltage source for operating the primary light source 23 having acurrent limit to less than 200 mA, less than 150 mA, less than 125 mA,or less than 100 mA.

In one embodiment, the device for irradiating the target tissue containsa battery 33 having a voltage of 3 V to 9 V (or up to 12 V), preferablyof 6 V, as a power source for the operation of the primary light source23.

In one embodiment, the device for irradiating the target tissue containsa battery 33 having a capacitance less than 3700 mAh. In a furtherembodiment, the capacitance of the battery 33 is from 50 to 3700 mAh,preferably less than 1500 mAh. In a further embodiment, the capacitanceof the battery is less than 200 mAh, or less than 150 mAh. In a specialembodiment, the capacitance of the battery is around 100 mAh, forexample, 90 mAh, 100 mAh, 105 mAh, i.e., approximately between 80 and120 mAh. In this special embodiment, with suitable selection of theprimary light source 23, the current for the operation of the primarylight source 23 can be produced by the limiting of the capacitance ofthe power source, so that even in the event of malfunction, a provisionof an excessive amount of power can be prevented as a safety measure,since the battery 33 itself cannot provide a sufficient amount ofenergy. In this case, the device for irradiating the target tissue musthave a device for simple replacement of the battery 33, preferably onthe upper side (on the side facing away from the target tissue or fromthe end face 25) of the device, or laterally. In a special embodiment,the battery 33 is permanently installed in the housing 34, so that itcannot be replaced by the user of the device.

In a further embodiment, a fuse is connected in the operating powercircuit to the primary light source 23. This fuse is to have a responsetime for interrupting the power circuit of less than one second, ideallyless than 0.1 second.

In a further embodiment, a timer for turning off the device (forexample, turning off the operating current, blocking the illumination ofthe target tissue, etc.) between 1 and 30 minutes of operating time orirradiation time is planned. In a further embodiment, this timer can bepreset to a specific point in time, for example, 15 minutes or 12minutes or 10 minutes or 9 minutes or 6 minutes or 3 minutes.

In specific embodiments, the timer can be set during the manufacturing,for example, if the irradiation power during the irradiation is notconstant, but rather, for example, has a decreasing curve, so that thechronological cumulative total energy during the treatment reaches thedesired value (for example, 5.4 J or 5.4 J/cm²), depending on the curveof the irradiation power.

The selection of the operating or irradiation time can be dependent, forexample, on the selected power, wavelength, intra-corneal agent, tissuethickness, etc.

In one specific embodiment, the device can be equipped with anapplanator for mechanically changing the cornea geometry by pressing theapplanator onto the tissue surface (for example, corneal surface). Thisapplanator can be embodied from material which is transparent to theselected wavelength of the light source 23 (for example, quartz glass)or material which is absorbent (for example, PMMA). The applanator canhave an arbitrary surface geometry toward the tissue (i.e., toward theend face 25 of the ring body 20). The surface geometry can also beplanar, convex, or concave. By way of the suitable selection of thesurface geometry, in one embodiment, the inhomogeneous beam geometry(intensity distribution) or the influence of the cornea 2, which iscurved peripherally in relation to the beam, can be compensated for, inthat a convex applanator (for example, centrally protruding or convex)is used.

The applanator can also be connected to a device for beam modification.Thus, for example, the applanator can be embodied as planar orthogonallyto the irradiation direction toward the target tissue (i.e., toward theend face 25 of the ring body 20) and as convex having an absorbentmaterial for the selected irradiation wavelength facing away from thetarget tissue in the direction of the primary light source 23. Theapplanation surface or the applanator can be embodied from a materialwhich is transparent or at least partially absorbent for the selectedlight wavelength in this case. If an applanator is used, it isintentionally accepted that the cornea 2 is touched by the applanator inthe irradiated region, however, in this case the stress of the cornea 2is less in comparison to fastening of the irradiation device in theirradiated region.

The suction ring 21 consists of two concentric bearing surfaces, forexample, the inner bearing surface 28 and the outer bearing surface 30,or bearing edges on the target tissue, which are separated from oneanother by a partial cavity and which can accommodate or build up thepartial vacuum for suctioning the device onto the target tissue.

The ring body 20 can be made of an arbitrary, preferably biocompatiblematerial. It can be manufactured, for example, from plastic (forexample, PMMA) or metal (steel, titanium, etc.). The ring body 20 cancontain or consist of a magnetic material. The light source 23 cancontain magnetic sensors (for example, Hall sensors), which detect themagnetic material upon insertion into the ring body 20 and can be used,for example, as the on switch for the light source 23. Other sensorsystems are also conceivable.

The ring body 20, for example, the suction ring 21, or the housingenvelope 39 can be equipped with a device, which enables wetting of thecornea 2 by means of water or aqueous solutions during the treatment.Thus, for example, the housing envelope 39 can have, up to a certainextent (for example, approximately 1 mL or less or also more, dependingon the device) on the window side (on the base 45), one or moreperforations, through which the water or the aqueous solution forwetting the cornea 2 slowly penetrates over the treatment time onto thecornea surface. The openings in the window (on the base 45) of thehousing envelope 39 are to be smaller than 1 mm if possible in thiscase, preferably smaller than 0.5 mm.

Considered technically, in the operationally-ready state, every sidewall of the housing envelope 39 and the housing 34, if it protrudesdistally (above) over the actual ring body 20 (receptacle), representsan extension of the ring body 20 and can be counted with the ring bodyor considered equivalent thereto if needed.

All elements of all embodiments are combinable with one another to formfurther, novel embodiments.

LIST OF REFERENCE NUMERALS

-   1 eye-   2 cornea-   3 longitudinal axis (axis of symmetry) of the device, axis of    symmetry of the eye-   4 front chamber of the eye (anterior chamber)-   5 rear chamber of the eye (posterior chamber)-   6 iris-   7 pupil-   8 retina-   9 sclera-   10 limbus-   11 --   12 --   13 --   14 --   15 --   16 --   17 --   18 --   19 exit opening (passage opening)-   20 ring body-   21 suction ring-   22 receptacle-   23 light source, irradiation source-   24 bearing edge-   25 end face-   26 irradiation channel-   27 inner bearing edge-   28 inner bearing surface-   29 suction surface-   30 outer bearing surface-   31 outer bearing edge-   32 electronics system, control electronics system-   33 battery (power source)-   34 housing-   35 stop limit on the housing 34-   36 stop limit on the receptacle 22-   37 distance between cornea 2 or corneal surface and the light source    23-   38 base (lower side of the housing 34, window)-   39 housing envelope-   40 stop limit on the housing envelope 39-   41 height difference between housing 34 and housing envelope 39-   42 upper edge of the housing envelope-   43 upper edge of the housing-   44 electrical connection between the functional elements, for    example, light source, electronics, and battery-   45 lower side of the housing envelope-   46 switch-   47 magnet-   48 inner wall of the ring body 20 or of the irradiation channel 26-   49 outer wall of the ring body 20-   50 cooling body (cooling device)-   51 contact surface between cooling body 50 and light source 23-   52-   53 --   54 --   55 --   56 --   57 --   58 --   59 --   60-   61 time curve of the irradiation power-   62 time curve of the cumulative power transferred to the cornea-   63 mean irradiation power, averaged over the irradiation time

1-14. (canceled) 15: A device for irradiating the cornea (2) of an eye (1), which comprises at least the following elements: a ring body (20), which has a bearing surface (28, 30) embodied concentrically about the longitudinal axis (3) of the device for the purpose of fastening the device on the eye (1), an irradiation channel (26) for irradiating the cornea (2), which is located inside the ring body (20), wherein the bearing surface (28, 30) for fastening the device is arranged outside the irradiation channel (26), wherein the device furthermore comprises a UV light source (23), which, in the operationally-ready state of the device, is attached inside the ring body (20) for emitting light in the irradiation channel (26). 16: The device according to claim 15, wherein the ring body (20) has a receptacle (22) for a housing (34), in which the UV light source (23) is attached, wherein in the operationally-ready state of the device, each side wall of the housing (34), if it protrudes distally beyond the ring body (20), represents an extension of the ring body (20). 17: The device according to claim 16, wherein the housing (34) has at least one control electronics system (32) or a power source (33). 18: The device according to claim 17, wherein light source (23), control electronics (32), and power source (33) are enclosed by the shared housing (34). 19: The device according to claim 16, wherein the device has a housing envelope (39), which has a stop-limited receptacle for the housing (34), wherein the housing envelope (39) itself can be introduced into the receptacle (22) for a housing, preferably in a stop-limited manner, and wherein in the operationally-ready state of the device, each side wall of the housing (34) and the housing envelope (39), if they protrude distally beyond the ring body (20), represent an extension of the ring body (20). 20: The device according to claim 19, wherein the housing envelope (39), in the operationally-ready state, encloses the housing (34) completely and in a leak-tight manner on the base and laterally and protrudes beyond the upper side thereof. 21: The device according to claim 19, wherein units for beam modification are provided inside the irradiation channel (26), and specifically outside the housing (34) and inside the housing envelope (39). 22: The device according to claim 15, wherein a control electronics system (32) is provided for the light source (23), using which the irradiation power is settable so that it decreases during the irradiation of the cornea. 23: The device according to claim 15, wherein a cooling device (50) is provided for dissipating the generated waste heat. 24: A method for irradiating the cornea (2) of an eye (1) using a device according to claim 15, wherein the device is fastened on the eye and the irradiation power is changed during the irradiation of the cornea (2). 25: The method according to claim 24, wherein the irradiation power is changed so that it decreases during the irradiation of the cornea (2). 